(1) Field of the Invention
This invention relates to ram-air flexible gliding wings, commonly referred to as "parafoils", and is directed more particularly to a parafoil having a cell inflation system providing for orderly cell inflation which reduces the usual high opening forces common in such devices.
(2) Description of the Prior Art
The inflation of a parafoil typically is a very rapid and dynamic process which often results in high and unacceptable opening forces. Before the cells of the parafoil are inflated, the shape of the canopy is highly irregular, and when the canopy unfolds, it is very roughly of a planar configuration exposing all cells to inflation more or less simultaneously, producing a large opening force.
Referring to FIGS. 1-3, one attempt to reduce the sudden large opening force typically experienced, includes reefing the central cells while permitting outer cells to be free to inflate (FIG. 1). Thereafter, cells on either side of a central cell are allowed to inflate (FIG. 2), and, finally, the central cell is allowed to inflate (FIG. 3). Thus, the cells are opened in stages in the span-wise direction, as illustrated in FIGS. 1-3. In practice, the reefing procedure has been found to require overly complex and time-consuming rigging of the parafoil.
Referring to FIGS. 4-7, another attempt to reduce the large opening force common in parafoils involves use of a slider, i.e., a ring in which are disposed all of the suspension lines. The slider holds the suspension lines close together momentarily to restrain the cells from rapid spread and inflation. The slider slides down the suspension line to regulate inflation. While helpful in some situations, the slider method is passive and does not provide active inflation control.
There thus remains a need for a parafoil assembly including means for effecting orderly cell inflation that produces relatively low opening forces.